Introduction
MLAG (Multi-chassis Link Aggregation Group) implementation in RouterOS allows configuring LACP bonds on two separate devices, while the client device believes to be connected on the same machine. This provides a physical redundancy in case of switch failure. All CRS3xx series devices can be configured with MLAG.
Quick setup
in this example, CRS317 and CRS309 devices are used as MLAG peers and any device with two SFP+ interfaces can be used as an LACP client, see a network scheme below.
First, configure bonding interface for MLAG on peer1 and peer2 devices, use a matching mlag-id setting on both peer devices:
/interface bonding add mlag-id=10 mode=802.3ad name=client-bond slaves=sfp-sfpplus2
Next, configure bridge with enabled vlan-filtering, and add needed interfaces as bridge ports. For the peer-port a dedicated untagged VLAN should be applied, thus pvid setting is used. Below are configuration commands for peer1 and peer2 devices:
/interface bridge add name=bridge1 vlan-filtering=yes /interface bridge port add bridge=bridge1 interface=sfp-sfpplus1 pvid=99 add bridge=bridge1 interface=client-bond
Last, specify bridge and peer-port to enable the MLAG. Below are commands for both peer devices:
/interface bridge mlag set bridge=bridge1 peer-port=sfp-sfpplus1